There are three known mammalian tachykinin receptors termed NK1, NK2 and NK3. All are members of the 7 transmembrane G-protein coupled receptor family and induce the activation of phospholipase C, producing inositol triphosphate (so called Gq-coupled). Inhibitors of NK-1, known as NK-1 receptor antagonists, can be used as antiemetic agents, such as the drug aprepitant. Binding The genes and receptor ligands are as follows: (Hökfelt et al., 2001; Page, 2004; Pennefather et al., 2004; Maggi, 2000) See also Substance P G protein coupled receptors References External links G protein-coupled receptors Molecular neuroscience